Rotary vane pump



Dec. 1, 1970 K. MUELLER 3,544,241

ROTARY VANE PUMP Filed Oct. 22, 1968 3 Sheets-Sheet 1 INVENTOR l l ll, #056 45k Dec. 1, 19 70 v K. MUELLER 3,544,241

ROTARY VANE PUMP V Filed 001;. 22, 1968 3 Sheets-Sheet 5 7Q iii-5! INVENTOR lZ/MA 19054 454 BY United States Patent 3,544,241 ROTARY VANE PUMP Karl Mueller, Ringstr. 6066, Rodenkirchen, Cologne, Germany Filed Oct. 22, 1968, Ser. No. 769,672 Claims priority, application Germany, Oct. 25, 1967, 1,628,332 Int. Cl. F04c 1/00; F01c 1/00 US. Cl. 418-35 Claims ABSTRACT OF THE DISCLOSURE A rotary pump has an inlet and an outlet on opposite sides of which a first chamber portion extends over a greater angle and a second chamber portion extends over a smaller angle. A stack of vanes is located in the first chamber portion, and the foremost vane of the stack is coupled with the rotor in the region of the inlet and transported by the rotor through the second chamber portion to the outlet, sucking fluid from the inlet and discharging fluid through the outlet until the transported vane passes the outlet and becomes the rearmost vane of the stack.

BACKGROUND OF THE INVENTION The present invention is concerned with a rotary vane pump which may be used as a vacuum pump, as a compressor, and also for transporting liquid and gaseous media.

Rotary vane pumps are known in which vanes intermittently rotate with a rotor, and form expanding and contracting chambers for sucking fluid into the expanding chambers, and discharging fluid from the contracting chambers.

SUMMARY OF THE INVENTION It is one object of the invention to provide an improved rotary vane pump in which the vanes do not continuously rotate with the rotor.

Another object of the invention is to provide a rotary vane pump in which only a single vane is rapidly moved to suck in and discharge fluid.

Another object of the invention is to provide a pump in which the inlet and the outlet can have very large cross sections and in which the pumped medium moves along a short and only slightly curved flow path between the inlet and the outlet of the pump.

Another object of the invention is to provide a rotary vane pump having low friction losses.

With these objects in view, the present invention relates to a rotary vane pump which comprises a stator; a rotor mounted in the stator and defining with the same a first chamber portion and a second chamber portion on opposite sides of an inlet and an outlet; a set of vanes forming a stack in the first chamber portion; coupling means for coupling the foremost vane in the region of the inlet with the rotor, and for disengaging the vane from the rotor in the region of the outlet; and control cam means for moving the foremost vane to a coupled position engaged by the coupling means.

While the respective vane is transported by the rotor through the second chamber portion from the inlet to the outlet, it sucks fluid through the inlet into the second chamber portion, and discharges fluid through the outlet from the second chamber portion until it passes the outlet and becomes the rearmost vane of the stack. As the transported vane is added to the stack, the same is moved in the direction of rotation so that its now foremost vane moves one step into the region of the inlet, where it is coupled with the rotor and transported by the same from the inlet to the outlet.

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In a preferred embodiment of the invention, the rotor has a central rotor portion and a pair of disc-shaped rotor side walls sliding along the lateral walls of the housing which is provided with circumferentially spaced inlet means and outlet means. Between the rotor and an annular inner surface of the stator, an annular space is formed which includes the first and second chamber portions on opposite sides of the inlet and outlet. The vanes extend in substantial radial direction between the center rotor portion and the rotor side walls to the annular inner stator surface. Coupling recesses in the center rotor portion and in the outermost end portion of the rotor side walls are spaced in circumferential direction angular distances corresponding to the spacing of the inlet and outlet along the second chamber portion.

Directly before the inlet, coupling portions of the foremost vane enter the coupling recesses in the rotor so that the foremost vane is coupled with the rotor and transported to the outlet, as explained above. Between the inlet and the outlet, a guide and sealing surface is provided which has a smaller radius than the remaining cylindrical surface portion of the inner stator surface so that the transported vane is held in the coupling recesses of the rotor until arriving at the outlet where it passes beyond the guide and sealing surface, and is moved out of the coupling recesses by the centrifugal force or by the action of gravity.

Depending on the amount of fluid which is to be pumped, at least two, but preferably between three and six vanes can be successively coupled with the rotor during one revolution of the same. The coupling of the vanes by entering the coupling recesses in the rotor can be obtained by gravity, if the rotor rotates comparatively slowly, or by rising and falling portions of the guide and sealing surface portion provided in the region of the inlet and outlet.

In the preferred embodiment of the invention, the inward coupling movement of the vanes is effected by spring means, or by fluid pressure, such as air pressure or oil pressure, the required force depending on the number of revolutions of the rotor. The required fluid pressure may be produced by the fluid pumped by the rotary vane pump.

As explained above, the stack of vanes is transported stepwise whenever a vane is added to the stack in the region of the outlet, and the rotating rotor side walls slidingly engage the lateral edges of the vanes forming the stack so that the stack is as a whole urged to rotate slowly to bring the foremost vane into the region of the inlet where it is coupled with the rotor rotating at a higher speed.

The novel features which are considered as characteristic for the invention are set forth in particular in the appended claims. The invention itself, however, both as to its construction and its method of operation, together with additional objects and advantages thereof, will be best understood from the following description of specific embodiments when read in connection with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWING FIG. 1 is a cross-sectional view illustrating an embodiment of the invention;

FIG. 2 is a cross-sectional view illustrating a preferred embodiment of the invention; and

FIG. 3 is an axial sectional view taken on line IIIIII in FIG. 2.

DESCRIPTION OF THE PREFERRED EMBODIMENTS The general arrangement of the embodiments illustrated in FIG. 1 and in FIGS. 2 and 3, respectively, is the same,

are shown to be spaced an angle of substantially 90, but

the angle may be within the range between 60 and 120. The rotor of the pump includes a rotor shaft 7 mounted in bearings 2a and 3a in'the lateral stator walls 2 and 3, and carrying a fixed central rotor portion 8. A pair of l rotor sidewalls 9 and is provided on opposite sides of the central rotor portion 8. The rotor side walls 9 and 10 slide on the inner faces of stator walls 2 and 3 with small play, and are mounted on a pair of fixed bushings 7a and 7b for axial movement. Dished springs 29 abut flanges of bushings 7a, 7b and rotor side walls 9 and 10, respectively, to urge the same toward each other and into abutment with the ends of the central rotor portion 8. At least one pin 70 passes through bores in rotor side walls 9, 10 and central rotor portion 8 to assure circumferential alignment of the rotor parts.

Between inlet 5 and outlet 6, a control means in the form of a curved body or lining 14 is secured to the inner circular surface of stator wall 1 so that the stator has an inner annular surface In including a cylindrical surface portion 20a of greater diameter, and a guide and sealing surface portion 20 whose ends 21 and 22 taper toward the inlet 5 and outlet 6, respectively.

Between the inner annular stator surface 1a composed of surface portions 20 and 2011, the rotor side walls 9 and 10, and the peripheral surface of the central rotor portion 8, an annular space is formed. Inlet 5 and outlet 6 divide the annular space into a first chamber portion 40a and a second chamber portion 40.

A stack of vanes 11, which have a substantially sectorshaped cross section, and are preferably hollow, is disposed in the first chamber portion 40a, only the foremost and rearmost vanes of the stack being shown in the drawing, while actually the first chamber portion 40a is completely filled with the stack of vanes 11 due to the sectorshape of the same.

Central rotor portion 8 has five peripheral angularly spaced coupling recesses 12.which are shaped to receive coupling portions 17 at the inner ends of vanes 11. Rotor side walls 9 and 10 have coupling recesses 13, respectively, which cooperate with axially projecting coupling portions 18 of vanes 11. Five pairs of outer coupling recesses 13 are provided, corresponding to the five inner coupling recesses 12, but the pairs of outer coupling recesses 13 lead the corresponding coupling recesses 12 in the direction of rotation indicated by the arrow, an angle between rotor passing through the respective recess 12.

The foremost vane 11' of the stack of vanes 11, taken in the direction of rotation, is shown in FIGS. 1 and 2 in a position to enter a coupling recess 12 while its leading face is located just before the inlet 5. In the embodiment of FIG. 1, the coupling portions 17 and 18 of the foremost vane 11 enter the corresponding coupling recesses 12 and 13 due to the force of gravity. In the embodiment of FIG.

2, a slide 31 is mounted in a substantially radial guideway of the annular stator wall 1, and is urged by spring means 16 radially inward to press against the radially outward edge 15 of the foremost vane 11' to push the coupling porportion 4 of annular wall 1. Instead of providing springs 16, channels, not shown, and filled with pressure fluid from the pump, may guide pressure fluid to the outer end of slide 31. The axial ends of slide 31 abut the peripheral surface 33 of rotor side walls 9 and 10. In the region of the coupling recesses 13, the peripheral surface 33 has shallow camming recesses 32 which permit inward movement of the slide and have trailing camming faces 34 which press slide 31 back to its outer position.

The lateral coupling portions 18 of vanes 11 may have resilient abutment faces so that the forces produced during the engagement of the coupling portions 18 with the coupling recesses 13 are small. It is advantageous to make vanes 11 hollow, and to construct the same of an elastic synthetic plastic material, such as polyamide or nylon.

When the foremost vane 11' is in the position shown in FIG. 2 in which coupling portions 17 and 18 have at least partly entered into the coupling recesses 12 and 13 in the rotor, it is moved by the rotating rotor in the direction of the arrow so that the outer end face 15 thereof slides along the rising slanted surface end portion 21 and is gradually moved inwardly to a position in which the coupling portions 17 and 18 fully engage the coupling recesses 12, and during movement through the working chamber portion 40, vane 11" is held in the coupling position by the guide and sealing surface 20. Since springs 29 urge rotor side walls 9 and 10 against the lateral edge of vanes 11, and also of vane 11", the working chamber 40 is divided into an expanding inletchamber, and a con tracting outlet chamber so that fluid is sucked from inlet 5, and discharged from outlet 6. When the rotor has transported an operative vane 11" to the region of the falling slanted surface end portion 22, the centrifugal force urges the transported vane 11" outwardly so that the coupling portions 17 and 18 thereof move out of the corresponding coupling recesses 12 and 13 of the rotor, and the transported vane is added to the stack of the vanes 11 as the rearmost vane, abutting the previously last vane of the stack which is pushed in the direction of rotation one step to place the next leading vane into the foremost position in which vane 11 is shown.

During each revolution of rotor shaft 7, five vanes 11 are transported from inlet 5 to outlet 6 and perform a pumping function. The volume pumped during each revolution of the rotor is the volume of the interior of the stator housing 1, 2, 3, less the volume of rotor side walls 10, 11 and the volume of the central rotor portion 8.

As explained above, the coupling recesses 13 lead corresponding coupling recesses 12 in the direction of rotation, and in the illustrated embodiment, the lead angle is, for example, 12. Since vanes 11 are not in radial position, but slanted to radial planes, the outer edge or face 15 of the transported vane 11" is in fluidtight sealing contact with the guide and sealing surface 20. The negative pressure of the expanding inlet chamber between inlet 5 and the transported vane 11" urges the transported vane 11" to turn about its inner end to a position tightly abutting the guide and sealing surface 20, while the slanted trailing face 25 tightly abuts a corresponding face 26 of coupling recess 12. Since coupling recesses 12 are axially extending grooves in the centralrotor portion, a fluidtight seal is obtained also at the inner end of the transported vane 11". I v

In the illustrated embodiment, thirty-one vanes are providedjof which not more than two vanes 11' and 11" are coupled with rotor 8, 9, 10. i

As explained above, the transported vane 11" is urged by the centrifugal force out of the respective coupling 1 recess 12 while moving along slanted surface 22 and tions 17 and 18 into the corresponding coupling recesses 12 and 13. The pressure of slide 31 can be adjusted by adjusting screws 35 Which are threaded into bores in a across outlet 6. The decoupling of th e transported vane 11" is aided by the camming effect of the trailing slanted surfaces 26 of coupling recesses 12 on the slanted faces 25 of the inner coupling portion 17.

During operation of the pump, the negative pressure in the expanding inlet chamber portion between the inlet and the transported vane 11", pulls rotor side walls 9 and 10 inwardly toward each other into tight sealing engagement with the lateral edges of the transported vane 11", whereas in the other angular regions of the pump, springs 29, or corresponding fluid pressure means urge the rotor side walls 9 and 10 toward each other.

Due to the frictional engagement between the inner faces of rotor side walls 9 and 10 and the vanes 11, 11' forming the stack of vanes, the entire stack is continuously urged to turn in the direction of rotation so that the size of the stack cannot increase by the addition of a transported vane 11" at the rear end of the stack. The speed of the rotor is sufliciently high so that each vane arriving in the foremost position in which vane 11' is shown, is immediately moved away from the stack and transported from the inlet 5 to the outlet 6.

If the initial coupling of the foremost vane 11 is to be accomplished by gravity, as in the embodiment of FIG. 1, the rotary speed of the rotor must be comparatively small, and the Weight of the vane 11 great, and the inlet 5 must be disposed above the rotor axis so that it is preferred to apply pressure to the outer end of the foremost vane 11, as described with reference to FIG. 2. Due to the fact that the vanes 11 are sector-shaped or wedge-shaped, only the foremost vane 11' located at the inlet 5 can enter With coupling projections 17 and 18 into coupling recesses 12 and 13.

The coupling recesses of the rotor may be spaced from each other between 60 and 120, so that three to six circumferentially spaced sets of coupling recesses can be provided in the rotor. The leading and trailing faces of the vanes advantageously define an angle between 6 and 12 with each other so that the chamber portion 40a is filled with a stack of vanes composed of between 20 and 45 vanes. The rising and falling surface portions 21 at the ends of the guide and sealing surface portion 20 of body 14, are preferably shaped in accordance with a sinusoidal function.

If the pump is operated as a vacuum pump at a high rotary speed, the transported vane 11" is thrown by inertia against the last vane of the stack when released by the coupling recesses. In order to brake the movement of the vane, the last vane of the stack can be spaced from outlet 6 so that when the vane 11 has passed the outlet, it is still angularly spaced from the last vane of the stack, whereby a closed chamber with a fluid cushion is formed. This chamber is connected by a narrow duct with the outlet, so that the inertia of the vane overcomes the resistance of the fluid cushion and assumes the required position as rearmost vane of the stack.

In order to keep friction losses small, the lower part of the stator housing is filled with a lubricating medium, for example oil. In the embodiment of FIGS. 2 and 3, the inner cylindrical surface portion 20a is provided with circumferentially extending lubricating grooves 30 so that the contacting areas of the outer vane edges and of cylindrical surface portion a are reduced. Oil pockets, not shown, may be provided in the annular wall 1 following outlet 6 so that oil mixed with gas or air accumulates in the pocket and is removed through channels, not shown, while the oil entering the grooves is free of gas.

It will be understood that each of the elements described above, or two or more together, may also find a useful application in other types of vane pumps diflering from the types described above.

While the invention has been illustrated and described as embodied in a pump in which the rotor transports successive vanes singly from the inlet to the outlet, while the remaining vanes form a stack on the other side of the inlet and outlet, it is not intended to be limited to the details shown, since various modifications and structural changes may be made Without departing in any way from the spirit of the present invention,

What is claimed as new and desired to be protected by Letters Patent is set forth in the appended claims.

1. Rotary vane pump comprising a stator including an inlet and an outlet circumferentially spaced from each other; a rotor mounted in said stator for rotation about an axis and definng with said stator an annualr space having a first chamber portion and a second chamber portion located on opposite sides of said axis and said inlet means and outlet means; a plurality of vanes located in said annular chamber and including a stack of vanes located in said annular chamber and including a stack of vanes abutting each other and located in said first chamber portion filling the same; coupling means on said rotor cooperating with said vanes, said vanes having a coupled position engaged by said coupling means and traveling with said rotor and a released position freely movable in circumferential direction in said annular space, the vanes of said stack being in said released position; and control means on said stator in said second chamber portion between said inlet and said outlet for moving the vane of said stack foremost in said direction of rotation in the region of said inlet to said coupled position, and for causing in the region of said outlet movement of said coupled vane to said released position whereby said coupled vane is transported by said rotor through said second chamber portion from said inlet to said outlet while sucking fluid from said inlet and discharging fluid through said outlet, and then abuts said stack as rearmost vane of the same in said direction of rotation.

2. Rotary vane pump as claimed in claim 1 wherein said control means include a cam face in the region of said inlet for moving said foremost vane to said coupled position.

3. Rotary vane pump comprising a stator including an annular wall having an inlet, an outlet circumferentially spaced from said inlet, and lateral end walls; a rotor mounted in said stator for rotation in one direction and defining with the same an annular space having a first chamber portion and a second chamber portion on opposite sides of said inlet and outlet, said annular wall of said stator having an annular inner stator surface including a cylindrical surface portion along said first chamber portion and an inwardly projecting guide and sealing surface portion along said second chamber portion between said inlet and said outlet; a set of substantially radially disposed vanes located in said annular space and forming a stack in said first chamber portion; and coupling means for coupling the vane of said stack foremost in said direction of rotation in the region of said inlet means with said rotor, said coupling means including coupling recesses formed in said rotor spaced angular distances corresponding to the angular spacing between said inlet and said outlet along said second chamber portion, and coupling portions formed on said vanes, whereby said coupling portions of said vanes are held between said inlet and said outlet in said coupling recesses in said rotor by said inwardly projecting guide and sealing surface portion and are released at the end of the same to move out of said coupling recesses after passing said guide and sealing surface portion whereby the respective vane is transported through said second chamber portion and sucks fluid from said inlet and discharges fluid through said outlet while transported from said inlet to said outlet by said rotor, and then becomes the rearmost vane of said stack.

4. Rotary vane pump as claimed in claim 3 wherein said foremost transported vane is moved by the centrifugal force or by gravity out of the respective coupling recess after passing said guiding and sealing surface portion.

5. Rotary vane pump as claimed in claim 3 wherein said rotor includes a central rotor portion formed with a first plurality of said coupling recesses, and two rotor side walls at the axial ends of said central rotor portion disposed inwardly adjacent said lateral end walls of said stator, said rotor side walls extending outward in radial direction to said annular inner stator surface; the outer end portions of said rotor side walls being formed with a second plurality of said coupling recesses; and wherein said coupling portions of 'said vanes include inner coupling portions moving into and'out of said coupling recesses in said central rotor portion, and outer coupling portions moving into and out of said coupling recesses in said rotor side walls for coupling said vanes successively with said rotor in the region of said inlet, and for decoupling said vanes successively in the region of said outlet.

6. Rotary vane pump as claimed in claim wherein said rotor has a horizontal axis; wherein said inletis located above said axis so that said foremost vane is upright and is urged by the force of gravity and by suction toward said rotor so thatsaid coupling portions of said foremost vane enter. into coupling recesses in said central rotor portion and in said rotor side walls.

7. Rotary vane pump as claimed in claim 5 including a slide mountedfor radial movement on said annular wall in said first chamber portion and adjacent said inlet,

and spring means for urging said slide inward in radial direction into engagement with the foremost vane of said stack so that said coupling portions of said foremost vane W are pressed into said coupling recesses of said rotor in the region of said inlet.

8. Rotary vane pump as claimed in claim 7 wherein said slide extends in axial direction and has end portions located outward of said rotor side walls, said rotor side walls having camming recesses receiving said end portions in the inner position of said slide, and camming said end portions and said slide in outward direction when moving beyond the same into said second chamber portion.

9. Rotary vane pump as claimed in claim 7 including adjusting screws in said annular wall for adjusting the tension of said spring means.

10. Rotary vane pump as claimed in claim 3 wherein said guide and sealing surface portion has a smaller radius than said cylindrical surface portion of said inner annular stator surface between said inlet and'said outlet, and has in the region of said inlet a slanted surface end portion for guiding said foremostvane inward from said cylindrical surface portion onto said guide and sealing surface portion.

11. Rotary vane pump as claimed in claim 10 wherein said guide and sealing surface portion has in the region of said outlet a slanted surface end portion for guiding said vane outward from said guide and sealing surface portion onto said cylindrical surface portion.

' 12. Rotary vane pump as claimed in claim 11 wherein said slanted surface end portions have in circumferential direction a sinusoidal shape.

13. Rotary vane pump as claimed in claim 3 wherein said annular wall includes a circular wall having a cylindrical inner surface, and a body having said guide and sealing surface. and secured to said cylindrical inner surface between said inlet and said outletso that the remainder of said cylindrical inner surface forms said cylindrical surface portion, the thickness of said body corresponding to the depth of said coupling recesses.

14. Rotary vane pump as claimed in claim 3 wherein said coupling recesses are spaced angular distances between 60 and 120 and said inlet and outlet are spaced a corresponding angular distance along said secondchamber portion; and wherein said rotor has at least one set of between three and six circumferentially spaced coupling recesses.

15. Rotary vane pump as claimed in claim 3 wherein said vanes have substantially sector shaped cross section in a plane perpendicular to the axis of rotation of said rotor, the leading and trailing faces of said vanes defining an angle between 6 and 12 with each other so that said first chamber portion is substantially filled with a stack of vanes composed of 20'to 45 vanes.

16. Rotary vane pump as claimed in claim 3 wherein said rotor includes a central rotor portion formed with a first plurality of said coupling recesses, and two rotor rotor.

8 side walls at the axial ends of said central-rotor portion disposed inwardly adjacent said lateral end walls of said stator, said rotor side walls extending outward in radial direction to said annular inner stator surface; the outer end portions of said rotor sidewalls being formed with a second plurality of said coupling recesses; wherein said coupling portions of said vanes include inner coupling portions moving into and out of said coupling recesses in said central rotor portion, and outer coupling portions moving into and out of said coupling'recesses in said rotor side walls for coupling'said vanes successively with said rotor inthe' region of said inlet, and for decoupling said vanes successively in the region of said outlet; and wherein said second plurality of said coupling recesses in said outer end portions of said rotor side wallslead said first plurality of coupling recesses in said central rotor portion between 10 and 20 in the direction of rotation of said rotor whereby said vanes are slanted to radii of said 17. Rotary vane pump as claimed in claim 16 wherein said outer ends of said rotor side walls are resilient in the region of said coupling recesses so that said outer coupling portions of said vanes are. resiliently coupled with 7 stator, said rotor side walls extending'outward in radial direction to said annular inner stator surface; the outer end portions of said rotor side walls being formed with a second plurality of said coupling recesses, sa1d rotor side walls being mounted for movement in axial direction toward and away from said central rotor portion; wherein said rotor includes resilient'means ax'ially outward of said rotor side walls for urging said rotor side walls toward each other and into sealing contact with saidvanes;

and wherein said coupling portions of said vanes include inner coupling portions moving into and out of sa1d cou- 'pling recesses in said central rotor portion, and outer coupling portions moving into and out of said coupling recesses in said rotor sidewalls for coupling sa1d vanes successively with said rotor in the region of said inlet, and

for decoupling said vanes successively in the region of said outlet.

20. Rotary vane pump as claimed claim 3 wherein the vane of said stack last in the direction of rotatlon of said rotor is spaced from said outlet so that the respective vane which moves with said rotor closes said outlet before abutting said rearmost vane formed between the moving vane and said last vane; and wherein said annular wall has a duct connecting said closed chamber with'said outlet so that said moving vane is braked before abutting said last vane and becoming the rearmost vane of said stack.

References Cited UNITED STATES PATENTS- 3,417,664 12/1968 Brucker .103216 2,952,249 9/ 196 0 Conover 103-216 2,118,589 5/1938 Carpenter f 1035129 479,080 7/1892 Snelling 91-60 7 530,220 12/1894 Delattre et al 9l60 FOREIGN PATENTS 970,004 9/1964 Great Britain. 702,107 1/1954 Great Britain. 602,337 2/1960 Italy.

HENRY F. RADUAZO, Primary Examiner 

